The use of electrodeposited metals to secure abrasive particles to a substrate is a well established practice in the abrasive industry. Conventional electroplating of abrasives involves depositing metal onto a substrate until a desired thickness is achieved. Abrasive particles such as diamond or cubic boron nitride are then introduced into the plating bath and are deposited on the plated metal. Further electrodeposition of metal affixes the abrasive particles to the substrate. As a result of this electrodeposition process a single layer of abrasive particles are affixed to the substrate by the electrodeposited metal coating.
One disadvantage associated with such abrasive articles is that the single layer of abrasive particles may be dulled, clogged with swarf and/or dislodged from the metal bond coat during an abrading process. As a result, the cutting efficiency of the abrasive article may be substantially deteriorated. A second disadvantage associated with such abrasive articles relates to the range of abrasive particles that can be utilized in this type of an abrasive article. Specifically, deposition of metal is not favored for affixing very fine grade abrasive particles (e.g., less than about 6 .mu.m) to a substrate because the metal thickness would substantially engulf the very fine grade abrasive particles. In such instances, the metal coating itself may contact the workpiece during the abrading process which may result in uncontrolled scratching of the workpiece.
One potential application for metal bond abrasive articles is in the finishing of magnetic memory disc substrates, for example, ceramics or glass ceramic substrates. In order to produce an acceptable magnetic memory disc, the memory disc substrate must have precisely controlled dimensions and a precisely controlled surface finish. Typically, dimensioning and imparting the desired surface finish to memory disc substrates has involved a multi-step process using loose abrasive slurries. In the first step of the process, the memory disc substrates are dimensioned such that they have the desired thickness and thickness uniformity. After dimensioning, the discs may then be textured to provide the desired surface finish.
Although loose abrasive slurries are widely used in these process, loose abrasive slurries have many disadvantages associated with them. These disadvantages include, for example, the inconvenience of handling the required large volumes of the slurry, the required agitation to prevent settling of the abrasive particles and to assure a uniform concentration of abrasive particles at the polishing interface, and the need for additional equipment to prepare, handle, and dispose of (or recover and recycle) the loose abrasive slurry. Additionally, the slurry itself must be periodically analyzed to assure its quality and dispersion stability. Furthermore, pump heads, valves, feed lines, grinding laps, and other parts of the slurry supply equipment which contact the loose abrasive slurry eventually show undesirable wear. Further, the processes which use the slurry are usually very untidy because the loose abrasive slurry, which is a viscous liquid, splatters easily and is difficult to contain.
In view of the foregoing, there is a need for an abrasive article having an increased useful life over conventional metal bond abrasive articles. Preferably, such an abrasive article will be suitable in a wide range of abrasive particle grades including very fine grades and may be suitable as a replacement for loose abrasive slurries to dimension and/or texture glass ceramic memory discs.